function add0(m){return m<10?'0'+m:m }
function datetime(timestamp)
{
  //timestamp是整数，否则要parseInt转换,不会出现少个0的情况

  var time = new Date(timestamp);
  var year = time.getFullYear();
  var month = time.getMonth()+1;
  var date = time.getDate();
  var hours = time.getHours();
  var minutes = time.getMinutes();
  var seconds = time.getSeconds();
  return year+'-'+add0(month)+'-'+add0(date)+' '+add0(hours)+':'+add0(minutes)+':'+add0(seconds);
}